Method and apparatus for severing grid strips into predetermined grid lengths



G. L. WHIPPLE4 MTHOD AND APPARATUS FOR SEVERING GRID STRIPS Jan. 15,1946.

2 sheets-sheet 1 I INTO PREDETERMINED GRID LENGTHS Filed June l llllli n Y m JF 1 wm 5,

. fwllrll ATTORNEY 5 l Jan. l5, 1946. G. L WHIPPLE z 2,392,870

METHOD AND APPARATUS FOR SEVERING GRID STRIPS INTO PREDETERMINED GRID LENGTHS Fl-ed June l, 1944 2 Sheets-Sheet 2 ATTORNEY:

E EI:

Patented Jan. 15, 1946 UNITED STATES *"PATEN T oFF-ICE i METHOD AND APPARATUS FOR sEvERrNG GRm STRIPS INT PREDETERMINED GRID LENGTHS George L. Whipple, Newark, N. J., assignor to y' Tung-Sol Lamp Works Inc., Newark, N. J., a corporation of Delaware' Application/June '1, 1944, Serial No. 538,298

;; parts I I. The frame I0 is of rectangular shape 17 claims.

and improved apparatus of the above indicated character which is characterized by its accuracy in operation, its simplicity and ease of operation and the economy with which it may be manufactured.

Further objects of the invention will hereinafter appear.

For a better understanding of the invention reference may be had to the accompanying drawings forming a part of this application-wherein Fig. 1 is a plan view of one embodiment ofthe invention; Y

Fig. 2 is a side view partly in section thereof;

Fig. 3 is an end view thereof;

Fig. 4 is a perspective view ofthe severingV knives; e

Fig. 5 is a perspective view of a grid strip;

Fig. 6 is a perspective view of one form of a grid ready for assembly; Y

in plan and of a length greater than that of the grid strip I. groove or channel I 2 is provided on the top of the frame I0, in this particular embodiment being Y formed by spaced strips or bars I 3 fastened to the Fig. '1 is a section through the knives at the A time of severing;

Fig. 8 is a plan view of a grid strip further illusy trating diagrammatically the severing operation;

Fig. 9 is a plan view of a modified apparatus; Fig. 10 is a side view thereof partly in section; and

Fig. 11 is an enlarged mechanism. z

Referring to Fig. 5, I have illustrated a lconventional grid strip I having the supporting wires 2 and 3 and the cross or lateral wires 4 wound plan view of a part of the thereabout. In Fig. 6 I have illustrated a grid length ready for assembly in a radio tube or the like which is omitted fromk the drawing for convenience in illustration. This grid length A hasv the support wires 2 and 3 severed at one end so as to be ofthe same length but severedatthe other end so as to have one endr5 projecting out beyondthe end-of the othersupport wire.

Referring to Figs. 1 to 4, I have illustratedan apparatus for forming the grid Vlengths A of pre-y determined length from the grid strip/I: in. accordance with this invention. This apparatus top of the frame I0 in any lsuitable manner as for example by the screws I4. The guide groove or channel I2 and side .bars I3 form a track on which is movably mounted a slide block or caririage I5. This carriage/I5 has at its righthand end a pair of clamps I6 and I1 forclamping and holdingV the' end o f a grid strip I with the grid strip disposed within the channelv I2. The two clamping' jaws I6 and I'I are relatively movable to receive andrelease the endsv of the grid strips ture I9 straddling a pin'2ll which is rigidly fastened to the carriage I5. The forked cam I9 is pivotally mounted at 2| to the upper end yof the pin 20 and is provided Awith an operating handle I9 for operating the cam and causing it to engage and disengage the strip I. YThe carriage I5 is held within the guide channel or track in am' suitable manner, as for example, eby providing the carriage I5 on each sidel thereof with a guide edge or ledge 22 which fits under the laterally projecting edge 23 formed in the bars I3. llvhe ledge 22 lmay be formed by milling theftop edge of the carriage I5 and the edge or flange 23 may be formed by making a bar I3. of two strips with the upper strip projecting beyond the lower one:

An index bar 25 underlies the carriage I5, be-

ing disposed in the particular embodiment shown in a groove l26 formed in the frame ill midway theV bars I3. This indexing bar isA adjustabllv but rigidly fastened within the'groove 2B to the frame in anyV suitable manner, Yas for example bythe screw lbolts 21 whose inner ends engage the side of the indexing bar 25, vIn the particular embodiment-shown the side of the bari is provided with elongated recesses 28 which recessed parts are engaged by the bolts 2l.` The indexing bar 25 is providedv with recesses 29 spaced from each other a distance equal to the length of the grid A and' in the particular embodiment shown, the grid'A for purposes of illus- I5 is locked against movement by Va means engaging successively these recesses 29 and in the comprises a frame I0 havingsupporting end or legv 55 particular embodiment shown this means com-` A longitudinally'extending guide l prises a pin 3D. The pin 3U may be removed from the recesses 29 by pressing down on a lever 3| which is pivotally fastened at 32 to a knob or pin 33 fastened to the upper side of the carriage I5, the other end Qft he lever 3 I beingvpivotally 5 fastened atg34to tlhempper end; o-fthepind; The lever 3`Ip'asses through a transverse opening or recess formed in the knob 33 and the lever is.A biased to locking position by means of a spring side of the carriage I5 and proj'ectingupintofsan opening 3l' formed in the lever 3I, the spring 36 engaging at one end the,=upper;side ofthe; carriage I5 and engaging atits1119131212@ntheeA lever 3l. guided in its up and down movements through the carriage I5 in an opening providedftlrerein.

The apparatus is provided with a severing i `means illustrated at the righthand end of the frame- IIll movablerest` oresupport 4-0'fo'verl-20 whiclr'- thei` gridj stripg I slidesn ase it* is" fedi` for.` ward' byetlie "carriage: I 51 is''mounted in-anysuite able: mannerrfor upward-'F movement towardL a" iixed` cutterrr 515',` the latterlieingjfixedy to the tramel I'by`means"ofboltsf56. 'K

On* each'side Vofthe support `4t) moves` a cutting; knife, a knife 4I"on tliegleftA lfrandsideY ofthe support 40; looking' at Fig.v 21 ,andfa knife 42`on the right'sideiof"the,supporti40l These knivesV are guided in azframe having riglit and leit 30 lever'qs is pxessedidownwardlyethen'manuany; 45 over toetherlefts. The-rodGIflis-externallyserew or.` otherwise:y In" the: particular uemlclodiment:v shown the. knives4 4 I .sandll 2e. areagrigidlyrfastened.; tdtneppposite -sidesrgnaiplate V4,1 'and-.the flatten is, engaged' byf thezleven` part; 5I v-; tol: actuata: the:-

knives. 1

l i -L d Also disposeda at theF rig-lithandl end; offthe;

machine, issaisupporting plate:=or f'bracket "meme-g ber: A52 Yandd amanua-lly operated ilever'f 53-h`avingfa,handlec54 is'fpivotally-ffastenedito tiret-bracket#- berf 53': 'having-*a lioldingfedge 54'; f(sesrFig.4 3l,

wliiclry is)v ad aptedrf to 1b`ey`b'1'ougntA dow-nf against thesupper sideI oftliegrid fstripf I lto lfiold'V it'tiglitly against 'the grid Ystripl restingonethe support# 46%- tingedges 51 g and-581 forL cooperativelyfunctionv ing with thefmovableflnives `4I-`and "42`ito sever-V the grid;V It is offthesametliicknesssasthe*supe port plate 40 andfisf supported'f'- in-aliner'nentvr therewithso that-whenthebknivesflll and*y 42'- 65 are moved^- upwardly.' theyfi telescopeVJ in*k close sliding` relationwith the fl'iredcutter 56';A The severing .knife 4I "cooperates 'with'l the 'cooperate' ing" severing edgez 58: of the cutter 5t?v to' sever'v evenfwitlr each other; The severingknifef 42eo-f op erativelyyfunctions withztheiflxedz ,cuttingredge 51,to severfone oie,thefsupportingawiresxz mp3s. asv for-exampleT the wire-3 at'arpointffurther; ina

The pin is enlarged at 30' and is 15s;

w of the upper ends of tension springs 41, the lower supporting wire 3 shorter than the supporting wire 2, or to provide the supporting wire 2 with Vthe projecting end 5. For this purpose the severing knife 42 is provided with a gap 42' for the accommodation of tljlepvrojecting end 5 oi the* wir`ea2,:and to thereby'savoidg severing this` projecting end5 from tlie support wire. The

Y severing edge 51 is provided with a correspond- *ing gap 51 which cooperates with the gap 42 so surrounding a pin 36 fastenedztoitheiuppenir10@ i wire 2" L" asstocleartheiprojecting end 5 of the support ends Jof ltlfl'e'springs n41 being attached to the fixed guide frame. The springs 41 bias the supporting plate`"to the position shown in Fig. 2, the plate being. arrestedi? in thatvposition against f-furtler movement underlthe 'ftensionf of 'the' springs: 'l'li`eupper edge of the plate .415'in*itszlowermosttpxz-` sition is@ spacedfromf ther support? platee 401- as indicatedatllmV ir'rv Fig: 2.a.but1when the;p1atef4'I-'. with the knives 4I iandfIlZiis.movedupwardly by-.f the lever `48iltlfie yupperf'edgeoftliesspacing:plate 4 i f engages-the z-lower edge fof tlfie:fsupporir'plate 4l!` and Emoves it up to the-'positionslioumin 7 against the tension of the springer* d The apparatusl isrprovided witli'i a measuring device or arm" 30 i for measuringa ther length or the rstizgri'd length ylliifitosle'e severed# fromn an end :of f'atstrip I z This armf I BDF-is -1carriedionifan adjustable shaft or rodtl .and mayfberbrought" down to a position in line with the strip-I'orfitf mays be-V-slfiiited:Y over outof alinement' with" lthe grid strip as for example to the positioneslfiowrn in dotand dash li'nezin-Fig: 33 Aplate=62 is earried fbyf the rod I'I l andftliisiplate 4carries 'afloweivv 6 Il when the latter f isfbrouglfit Adow-mito :exposition in alinement with the grid strip. Tl'lis-platevisA also providedV with'fa pin'f64forgfengagingftlie-urrderside of the arm Eilllfwli'enrth'el latterfisflshifted threaded and mounted for longitudinal adjusts ment on theframe'- IIL?V In' thefparticular enr bodimentshow-n thisfrod 6`fI '-isffjournaled `in alified provided for adjusting the rod lngitudinally:f By adjusting these :nuts 63 and B11 -tliearmv 60 mayfbe fbroughtl'closerftoordafrther awayjfromthe severing: block-f' 402i 'Illiefnut 6 1Cisl disposed 52 at: 52k 'I'hisg-lever 531carriessaholdingmerrr-im 55 between":th`e bearings -55ivforvmovingf theL rod -and Y adjusting it to the desired position and the nutre adjacent recesses29"ot'v'tl'iendexingfban 255- Tne operationA as follows Y A; grise strlpf I is placed fin positionswith one end rrnlyi'clamped between :tliei jaws I 6 and I 'I3of-ftiedclanipf'fof'tliel "'carrier. Asuefereindicatedlangarm1 su'jlisfaur j usted? to positionsuch thatf' its distanne-from'- the support' 4D isf equal t@ the1 spacing between* the centers {offadj acent recesses 2295er thejindex; ingban`r With thisladjustmentrmade-rthef cari- Y nage lsfis m-wea-i'forwardunanime-enqsQetiie` botlr: of: the f suplmrtingff-` wires i121? and 3-1'1 at points 70 the :indexingv b'ar2 5ssmovedlongitudinallyfuntilii theelocking pi130 entersinto afi'eces'si2@Sandi-ltrJ lthisi positionit'lrie,`v barzfsis sifst'enedhibytiidbbifs ward, namely at the point 3 so as to make the 76 21. 'Ihe arm 60 is then moved out of the path o1' the grid strip. The severing knivesl 4I and'42 are then actuated to sever the grid length-'A and then the carriage I is released by withdrawing the pin 38 from the recessesV 29 and is moved forward to the next indexing position with the pin 3i) automatically entering the next recess. The knives are again actuated to sever the grid length A and this is continued unti1 the strip is completely severed into the parts. The first movement of the actuating lever 48, 5I results in the sliding of the knives dI, 42 along the sides of the support plate 4l] until the cutting edges of the knives are disposed beyond the upper part of the supporting plate 4D a predetermined distance, and further movement of the lever 48 results in the movement in unison of the knives 4I and 42 and the support platev 4!) against the tension of the springs 41, the iinal severing position being shown in Fig. 7 wherein the cutting edges `of the knives 4I and 42 have slid past the cutting edges of the xed cutting knife 56.

Figs. '1 and 8 show the severing operation, it being observed that the wire 2 is severed only once each time while the wire 3 is severed at two points spaced the distance between the knives 4I and 42, a section B8 of the wire 3 being removed from the end 3 of the wire 3. By this mechanism the grid lengths A are of the exact predetermined form and lengths required for precision work on small or miniature radio tubes, the lengths of the sections being identical. For radio tubes having gridsof lengths diiering from that of grid A, an indexing bar 25 is used having the required spacing of the indexing notches 29.

In the embodiment of Figs. 9, and 11, the specific indexing means of Figures 1 to 3 is omitted and an electrical measuring and indexing means is provided. The frame is provided with the guide channel I2 and the guide rails I3 as in the rst embodiment and a carriage 1l! is guided therein having a knob 1I for facilitating the moving of the same manually longitudinally of the device. The carriage 10T is provided with clamping jaws I6 and I1 similar generally to the clamping jaws of the carriage above described with the clamping jaws I1 pivoted tol i bodiment comprises a support supporting an electromagnetic coil 18 having a core 11. The

tion to beengaged by theV lateralwire 4 of the grid strip. The electromagnet and its frame are adjustable towardand away from'the severing block 40 to obtain the length of grid A desired.Vv

vThe operation is .as follows. With thegrid strip I clamped inthe clamps I6 and I1 the carmagnetic circuit for this magnet comprises a tery 84 which is illustrated as having one side connected through a wire 85 to the frame or bar Y 18 and the other sid'e connected through a wire 86 with one terminal of the coil. The other terminal of the coil is connected through la wire 81 with a vertical cat Whisker terminal 88. This cat Whisker terminal projects up into the slot between the fingers or abutment lugs 83 in apasiriage 10 is moved forward until the wires 2 and 3 of the end of the vstrip engage the abutments 83. Sufficient pressure continues to be exerted on the carriage 'Ill to move the bar 8l) against the spring 8l until the contact 88 engages the end' strand of lateral wire 4. When this happens the electromagnet is energized and magnetically' locks the metal bar 80 rmly in the (position in which it was at the time the contact 88 makes the contact Iwith lateral wire. The forward movement ofthe carriage is therefore arrested and in this position tlhe grid length A is severed. lWhen the gridV length A is severed or choppedf off it automatically falls down and the circuit `through the electromagnet is automatically broken. The spring 8I thereupon returns the bar to the initial position whereupon the grid strip may be then advanced again for. repeating the operation. These Operations are repeated until all of the grid strip has been chopped into individual lengths.

I claim:

l. A means for severing grid strips of two lon- `:gitudinal wires connected together with cross wires into grids of predetermined lengths comprising a frame, a guide track thereon, a carriage Imovable on said track and having a clamp for clamping a grid strip, means for arresting the -lmofvemenit of the carriage after its advance a distance along the track proportional to the length of the grid to be severed, and. severing means in alinement with the track for severing from the grid strip a. grid while thus arrested.

2.' A means for severing grid strips of two longitudinal wires connected together with cross wires intogrids of predetermined lengths comprising. a. frame, a guide track thereon, a carfor clamping a grid strip, means for arresting the movement of the carriage after its advance a distance along the track proportional to the length of the grid to .be severed, and severing means in alinement with the track for severing from the z'grid strip a grid while thus arrested, said arresting means comprising a locking mechanism for locking the carriage tothe frame after each advance ofa predetermined length.

3. A means for severing grid strips into grids of predetermined lengths for use in thermionic tubes comprising a frame, a guide track thereon, a carriage movable on said track and having a clamp for clampinga grid strip, means for arresting the movement of the carriage after itsl advance a distance along the track proportional to the length of the grid to be severed, and severing means in alinement with the track for severing from the grid strip a grid while thus arrested, said arresting means comprising an electromagnet energized' after each predetermined advance of the carriage.

4. A means for severing grid strips of two longitudinal. wires connected together with cross wires into grids of predetermined lengths comprising a frame, a guide track thereon, a carriage movable on vsaid track and having a clamp for clamping a grid strip, means for arresting the movement ofthe carriage after its advanceva distance along the ,trackV proportional to the length-Pf, the sridia'be Severed and severing meanszm annementminane traenfrerserermg fromsthegrfd strip algrid While thus arrested...

said r arresting v. means :comprising 1an. index :bar having spacedLperforationsthereim andfa locking. pin carried by the-.1 carriage-.and :biased vto enter said perforations las the :carriage fis- .advanced steptby'step. i

5.` A means ior. severing: 'grid' stripsiintolgliidsr ot Vrn'edetermined lengths -for use inwtherniionixr tubes comprising sa frame, aguideftracki thereonr a carriage. movableon" said track and iv having a. clamp for clamping fa .grid stripameansffor air-1 resting themovement of thercarria'ge aitenitszadvence-a distance along thetra'ckiprnportinnallto theJlength of the grid to besseveredianctseverlng meansinin alinem'ent with :the track for severing from the. grid strip :aigrid'ivvhilefthus: 'arreste1if,. said arrestingtm'eans .comprislngnan indexbam having ispaced perforationstherein Tand a; loci(- ing pin carried bythe carriage. and :biased: toieniter said perforations. as 'the .carriagezls .advanned step by' 'Stepp said indexing bar .beingf adjustable. longitudinally of theframe.4

6. A. means .forsevering gridcstripsaintogrids of predetermined lengths for' usefirr thermionic tubes comprisingiaframara guide track thereon, a carriage movable on sadtrack mid'having a. clamp for clamping a grid strip, meansionarresting themovement. oiitliefcarriagezaitemits advance a distance:l alongythef track proportionalto the. length. .of .the grid' be severed, severing means in alinement: with -thetrack for severing from `the gridstripagrd while ,thusrarrestedn said arresting means comprisingan index bar having spaced periorations therein'. and-alcoliingzpin carried by the*` carriage rand; biased tto; enter said perforations .asz the: carriage. ia actvanced step by step,..said indexing, bar beingiad. justable longitudinally of;the;frame,.and:a -measi-` uring arm. disposed on the: oppositevsideso the severing mechanism from thecarriage andv adapt.- ed to engage the free. endof a grid strip.

'7. A means for severing. grid strips, into-grids of predetermined lengths for usednthermionic tubes comprising aframe, a-iguide track thereom. a carriage movable on.. said track. and having. :a clamp for clampingav grid strip; means for ,ariresting the movement of. the carriageiafterits advance a distance along the track. proportional to the length 'oi thegrid to be'severed-,tsevering means in. alinement with the track forsevering from the grid strip a. grid while. thus arrestedsaid. arresting means .comprising'anzindexrbar-having. spaced perforationsthereinandv 'a locking. pin carried by the, carriage and biased toi enter-said perforations as the1carriage is advancedstep .by step,A said indexing, har being. adjustable longitu-f dinally of the frame',y and a measuring armrdis'- posed on the oppositeside of thesevering mechanism from the carriage and adapted.` toengage the free end of a grid strip,;said-measurng -arm being; adjustably mounted to'assurne diierent positions with respecttothe severing` means.

8.. A means for severing-gridstripsof tvvalorbr gitudinal Wires connected together- Vwith cross wires into grids of predetermined-lengths coin'.-r prisinga framega guide track thereon, a-.carria'ge movable. on saidtrack'. and. having a.-clamp: forA alin'ement with thetrack for severing -rom-the grid stripa-grid vir-hilo thusarrestedsaitl severing :reagiere seveng knisresimonntedzoxr .the opposite .sides ofrthaseveringn blooiasafholder whiclris movable intoenga'gement withfa grid strip to holditiirmlyaupon tiieiseveringblock'andl means for actuatingttheseveringikniveszto sever the `grid.

:aiAimeans for severing; grid. strips oirtwoilongitudlnal 'Wires f connected togetherwith. cross. whesintgrldsof predetermined .lengths com-.- prisngsa frame,.a guldertrack thereonV a carriagemovabie' on. said: track and. having. a clamp forclampingaigrld stripgmeans for arresting-the movement-ofthe carriage .after its advance a distance.-y along the: track. porportional to: the length ofathesgrid. towloe;severedy and severing means in alinement.-with` the track for. severing froml the gridi stript-a gridvvhile thusarrestedsaid sever-f ingrmeans comprising a severing block,v apair of; severing knivesgmountedcn the opposite sides. ofrftheseveringbloek,aholder which is movableinto engagement withagrid stripfto hold itrm' ly uponztheseverlngblo'ck and means for actuatingfthexsevering knives to sever the grid,Y said holderfhaving severing edges cooperativelyfunctioning; with thevsevering knives andv one coop erating pair of knives havingggaps therein to clear one ofV the longitudinal wires.

yflf. Almeans for severlnggridstrips of two longitudinal wires-'connected together with, cross wiresintoigrids .of predetermined lengths corn-v .v prsi'ng a..irame agilide trackthereoma carriage' movablexontsaidtrack. and having a clamp for clampingia. grid. strip, `means for. arresting the movementof the carriageaafter'its advance a distance 'along the track proportionaly tol .the length of the.- grid; to. be severed and severing means 'in alinement lwith the track for severingfrom the grdstrip a". grid-'WhileV thus arrested, said arrestingmeans comprising` an indextbar having spaced periorations therein and a locking pin l carried by thecarriage' and biased to enter said. perforations; as the carriage is advanced step bystep,v therindexing bar beingY removable.

il.. A means for severing vgrid strips into grids oigpredetermined. lengths for use. in thermionic tubestcomprising. a frame; au guide track` thereon.y a .carriagejmovablei onsaid. track and` having a clamp-'for '.clampingargrid strip, means for arresting'the movement of the carriage after its advance-.a distance along the track proportional tothe length of` the Agridto be severed, and severing, meansin alinement. with the track lfor sever-l ngfromthegridtstripragrid while thus arrested, said arresting means comprising an electromagnet energized; aftereach. predetermined. advance ofthe carriage and. said electromagnet beingl dis posed on the opposite side of the severing means from the'carriage and comprising a spring biased movable magnetic bar in-line with the track,vsaid magnetic bar beingengaged by a support wireoi. the grid'stripto move the bar against its bias and a contact disposed in the-,path of the lateral wire of the. grid strip' for energizing the magnet upon contact .therewith and. locking the magnetic bar against. further. movement.

.12. A means" for severing gridvstrips of two longitudinal Wires connected. together with cross wires into grids of predetermined lengths com-v alinement with the' track' for severing from the grid strip-'agrid while thus` arrested; said arrest"-r ing means comprising an electromagnet energized after each predetermined advance of the carriage and said electromagnet being disposed on the opposite side of the severing vmeans from the carriage and comprising a spring biased magnetic bar in line with the track, said magnetic bar being engaged by a longitudinal wire of the grip strip to move the bar against its bias and a contact disposed in the path of the cross wire of the grid strip for energizing the magnet upon contact therewith and locking the magnetic bar against further movement and said bar being slotted at its end to have a pair of spring abutments for engagement with the longitudinal wires of the grid strip and said contact extending up into said slot and in the path of the advancing cross wires of the grid.

13. A severing means for grid strips comprising relatively movable severing knives, a biased arresting member disposed in the path of the grid strip and adapted to be engaged by the same, an electromagnet, and a circuit for said electromagnet comprising a contact disposed in the path of the grid strip and closed upon movement of said arresting member to lock the latter against further movement.

14. A means for measuring a grid length on a grid strip comprising an electromagnet and magnetic circuit, a movable member which is locked against movement by the electromagnet, and

means controlled by the engagement of the strip with said member forcontrolling the circuit to the magnet. Y 15. severing means for severing the two longitudinal wires of a grid strip comprising a xed knife having a cutting edge and a movable knife adapted to be brought to a telescoping position with respect to the xed knife to sever a grid from a strip by simultaneously severing both wires thereof.

16. A severing means for a grid comprising 'a iixed knife having a pair of spaced cutting edges, a pair of movable spaced knives adapted to be brought into telescopic lrelation with the cutting edges of the fixed knife, a movable supporting member for a grid strip disposed between said pair of movable knives and movable relatively thereto, said supporting member being biased to a denite position, means for bringing the pair of knives and the supporting member against the biasing means into severing relation with respect to the iixed knife edges, and movable holding means adapted to be brought into engagement with a grid resting upon the support member.

17. A severing means for a grid comprising a fixed knife having a pair of spaced cutting edges, a pair of movable spaced knives adapted to be brought into telescopic relation with the cutting edges of the xed knife, a movable supporting member for a grid strip disposed between said pair4 of movable knives and movable relatively thereto, said supporting member being biased to a denite position, means for bringing the pair of knives and the supporting member against the biasing means into severing relation with respect to the xed knife edges, and movable holding means adapted to be brought into engagement with a grid resting upon the support member, the grid strip having two wires and the cooperating knife edges on one side being adapted to sever both support wires of a grid on a line at right angles to the wires, and the other cooperating knife edges being adapted to sever only one of the wires.

GEORGE L. WHIPPLE. 

